According to an ancient Korean myth, fire dogs sent by a power hungry king attempt to steal the fiery sun or ice cold moon. When they bite either orb, an eclipse results.
But on August 21st, as parts of the United States are treated to a total solar eclipse, astronomers all over the country will not be searching for these creatures. Instead, they shall be taking part in experiments to try to understand the plasma around the Sun, the Earth’s atmosphere and the ability of life to survive beyond Earth.
Researchers at Weill Cornell Medicine will be analyzing data gathered during one such experiment. Spearheaded by Montana State University, over 50 high-altitude balloons will be sent into Earth’s stratosphere to livestream footage of the event. 34 of these balloons will be carrying samples of bacteria.
Each balloon will carry a small metal card, coated with spores of the harmless bacterium Paenibacillus xerothermodurans. These spores are resistant structures that the bacterium utilizes to survive in unfavorable conditions. An identical card will stay on the ground to allow researchers to compare, among other things, the spore’s survival and any bacterial mutations.
“Our collaborators at NASA recently isolated this strain of Paenibacillus xerothermodurans and found it was highly heat-resistant. We now want to see whether it can withstand other extreme conditions in its spore state and how it does so,” said Prof. Christopher Mason, physiology and biophysics at Weill Cornell Medicine,.
According to Mason, the eclipse presents researchers with an excellent opportunity to study the effect of Mars-like conditions on the bacteria.
“The stratosphere is a Mars analog environment, combining low temperature, low atmospheric pressure, low humidity and high radiation conditions in a way that are nearly impossible to replicate in a laboratory setting,” Mason said.
Though atmospheric ultraviolet levels are usually higher than those seen on Mars, the moon blocks certain types of UV radiation during the eclipse, bridging this difference and bringing atmospheric temperatures down further.
“Characterizing bacteria capable of surviving in the stratosphere can help identify potential contaminants of extraterrestrial bodies from human space exploration — called Planetary Protection — and provide insight into microbial adaptation and the limits of habitability as we search for life beyond Earth,“ Mason said.
With this in mind, a key feature researchers will be examining is the bacterium’s RNA expression, the process by which information from genes is used to create a functional product, often proteins.
“We will first be characterizing the differences in RNA expression between cells in the vegetative state and the spore state. Previous studies have found low RNA expression in bacterial spores, but haven’t looked at this species or used modern techniques like RNA-sequencing. Depending on how quickly we can retrieve the samples and preserve RNA, we’ll then look at whether exposure to stratospheric conditions affects RNA expression,” Mason said.
With NASA and private entities locked in a race to put a man on Mars, experiments like these could help shed light on the genetic mutations that take place in such conditions. Mason expects to see pyrimidine dimers or molecular lesions on the bacterium’s RNA due to UV exposure. In humans, such lesions are the primary cause of melanomas.
Furthermore, according to Mason, recent studies of bacteria isolated from spacecraft assembly facilities found that stratospheric conditions induced substitutions of different bases in DNA, without any being added or deleted and something similar may be seen during the eclipse.
“The experiment will help determine whether this particular species is capable of survival beyond Earth. If it does show significantly increased survival, or even partial survival, compared to other species that NASA considers potential contaminants, then that could in theory guide changes to existing procedures [used to prevent contamination of extraterrestrial bodies]. This has yet to be determined though,” Mason said.